Dehydrator



F. W. HARRIS.

DEHYDRATOR.

APPLICATION FILED SEPT. L 1920.

Patented Sept 26, 1922..

2 SHEETS-SHEET l. @0

F. W. HARRIS.

DEHYDRATOR.

APPLICATION FILED SEPT. 1, 1920.

Patented Sept. 26, 1922 2 SHEETS-SHEET 2- Patente Sept. 26, 1922.

A TENT OFFICE.

FORD W. HARRIS, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO PETROLEUM RECTI- FYING COMPANY OF CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA, A CORPO- RATION OF CALIFORNIA.

DEHYDRATOR.

Application filed September 7, 192( Serial No. 408,694.

To all whom it may concern:

Be it known that I, FORD W. HARRIS, a citizen of the United States, residing at Los Angeles, county of Los Angeles, and State of California, have invented a new and useful Dehydrator, of which the ,fol lowing is a specification.

My invention relates to dehydrators, and the principal object of the invention is to provide a device of this character by which v liquids of different electrical conductivity and specific gravity may be readily separated.

A further object of the invention is to provide a dehydrator which is especially adapted to separate water and oil, and which finds a special utility in the dehydration of petroleum emulsions. Petroleum emulsions as produced in the production and transportation of oil consist of masses of oil in which globules of water are present. Where these globules are of such size as to be visible to naked eye, it is comparatively easy to separate the water and oil by allowing the emulsion to stand, the oil bein lighter than the water which settles readily in the bottom of the container. There are, however, emulsions inwhich the drops are so small that they are not visible to the naked eye and in which are also drops which are probably too small to be seen with even the most powerful microsco e. These very small drops of water wil not settle out even if the emulsion is allowed to stand for it long period, and it is a particularobject of my invention to provide a dehydrator by which these very tight emulsions may be separated.

It is a well known fact that when an emulsion is placed between electrodes, having' an electrical potential impressed there- -between, that the water particles tend to coalesce and tend to form larger drops, this action continuing until the drops continue to be of sufiicient size to readily settle trodes.

minimum potential necessary depends upon the average size of the water particles, the finer the particles, the higher the necessary potential. Where light oils of low specific gravity are involved, the size of the 'drop is always very small as thelarger particles readily settle out, and the voltage must be excesslve to prevent short circuit- I have further found that in the case of very light oils, the necessary voltage which prevents short circuiting may be in excess of 200,000 volts. It is extremely diflicult to build apparatus on which these excessive voltages may be carried, and it is a further object of my invention to provide a dehydrator which will treat very tight and stubborn emulsions with a voltage very much lower than that which would be otherwise necessary. This I' accomplish by agitating the emulsion in the electric field. I am aware that revious inventors have proposed to use agitation for this purpose,

butso far as I am aware, all previous types of apparatus designed for this purpose have been open to objection in that they were subject to a very considerable fire risk. This has been due to the fact that previous inventors have found it necessary, due to the peculiar construction of their apparatus, to dehydrate in tanks which were open to the atmosphere. I

It is a further object of my invention to provide a dehydrator in which charged electrodes are placed and in which the emulsion is agitated in the electric field. This, I accomplish by rotating one of the elec- I am aware that previou'smventors have provided a rotating electrode for this purpose, but they have .consldered it shown, 1 is a tight tank having an oil inlet necessary to insulate this rotating electrode from the tank structure, and they have met with many difficulties in providing an electrode which could be rotated and at the same time insulated against the potentials of 10,000 volts or more which it is necessary to employ. This ll obviate by providing a stationary inner electrode which is insulated from the tank surrounding this electrode with a rotating outer electrode which is grounded to the tank proper. By providing a structure of this character, T am able to use verysimple insulating means for the stationary inner electrode, and T am thereby able to provide a closed tank thus shutting oil the oilfrom all contact with the air and preventing explosions andi'ires.

lln previous typeset hydrator, using rotating electrodes, it has been thou ht necessary to provide an auxiliary settling tank and to pass the emulsion downwardly through the treater. T have found that it is entirely possible to treat many kinds of -oil and settle out the water in the same apparatus.

It has been found that "in all types of electric dehydrators, that there is a tendency for short circuiting chain to form when the dehydrator is first filled with very Wet oil, but if the circuit is momentarily interrupted, especially where the emulsion is 'in motion that these chains are broken up. '1 have further found that during the formation of these chains that the coalescence takes place and that after the short .circuiting chains have formed within the dehydrator, it is completely short circuited and no further dehydrating action takes place.

It is a further object of my invention toprovidemean's for interrupting the circuit to the dehydrator during predetermined intervals, in the event that the current flowing between the charged electrodes in the dehydrator exceeds a certain predetermined value.

A further object of my invention is to provide means for shutting off the flow of oil to the dehydrator whenever the current exceeds a certain value. 7

Further objects and advantages will be. made evident hereinafter.

Referring to' the drawings which are for illustrative purposes only,

Fig. 1 is a side elevation partly in section of a diagrammatic form of my invention.

Fig. 2 is a section on a plane represented by the line 22 of Fig. 1.

In the embodiment of my invention pipe 2, a clean oil outlet pipe 3, and a water outlet pipe 4. Suspended on an insulator 5 from the top 6 of the by means of a rod 7, is inner cylindrical stationary electrode having a bevel gear 19. The bevel gear 19 meshes with a bevel gear 20 carried on a shaft 21 which passes through a stufiing box 22 in the side of the tanld 1 and which is driven by a pulley 23, the pulley 23 being driven by any convenient source 01 power, not shown. The'shaft21 is supported in bearing 24 carried on plate 25, on which the bearing 18 is also carried. The emulsion inlet pipe 2 communicates with a. ring 26 having perforations 27 in the upper surface thereof through which the emulsion is distributed evenly around the outside of the tank l. The water outlet pipe 4 communicates through a valve 28 with a vertical riser 29 which is vented at the top as shown at 30 and which communicates with a second riser 31 which communicates through a pipe 32 with a suitable drain, not shown.

An electrical potential may be impressed between the stationary electrode 8 and the rotating electrode 10, by means of a transformer 33 having a primary 34, and a secondary 35. The secondary 35 is connected through a wire 36with the rod 7, Which passes through the insulator 5, the second ary 35 also being connected with the tank 1. The rotating electrode 10 is solidly grounded to the tank 1, the stationary inner electrode 8 being insulated by the insulator 5. The

which projects a stem 40 which carries moving contacts 41. The moving contacts 41 normally restsf against and connects contacts 42 which are also in series with the 0011 38 and the primary 34. The stem 40 is provided with a head 43 which extends into a' recess 44 in the core 39 as shown in Fig. 1.. @n the lower portion of the stem 40 is a plunger 45 moving in a dash pot 46, having a check valve 47. Also connected in series with the coil 38, the primary 34 and the contacts 42 is a coil 48 or an electrically operated valve 49. The coil 48 acts upon a core I sion supply,-

' age and frequency,

50 which .tends to hold a valve member 51 in the position shown, thus opening a passage from an emulsion inlet pipe 52 into the emulsion inlet pipe 2. A reactance 53 is also connected in series with the secondary 34.

The method of operation is asfollows: Pipe 52 is connected to the source of emul emulsio being forced by a pump or by gravity through the pipe 52 and pipe'2 into the ring 26 and through the perforations, 27 into the lower portion of the tank 1. Any air which may be in this tank is forced outwardlythrough the pipe 3 and which is at the extreme top of the tank. Whenever the tank is filled, all air is excluded therefrom and there is no dangerof' explosion. Current being supplied to wires 54 and 55 at any convenient voltthis current passes from the wire, 55. across the contacts 42 throughthe coil 48 through the coil 38 through the primary 34, the reactance 53 and back to the wire 54 to the source of supply. A certain potential is induced in the secondary and an alternating electro-motive force is impressed between the stationary inner cylindrical electrode 8 and the rotating outer' I electrode 10. This outer electrode 10 is roflows downwardly between the During the earlier portion tated at a slow rate of speed, s ay'at fifty revolutions per minute. The angle 1rons'11 are inclined as shown in Fig.1. The entire body of emulsion, oil and water inthe tank 1 is therefore set into slow rotation about the axis of the tank 1 due to the impelling actio of the angle-irons 11. Due

also to the inclination of these angle irons, the emulsion is forced downwardly in the space 9, the direction of rotation being 1n a counter clockwise direction as viewe in Fig. 2. There are, therefore, two motions,

first the rotation of the emulsion, and secondarily, a circulation of emulsion which electrode 8 and the tank 1, in the space 9, and upwardly inside the electrode 8. During this very slow circulation, water tends to drop out of the oil falling in the bottom of the tank 1 and the clean oil tends to rise to the extreme top of the tank, being withdrawnthrough the pipe 3. In the event chains start to form, short circuiting the electrodes, the current becomes excessive and the core 39 is pulled violently up in the coil 38. of its movement, the core 39 moves free with relation to the stem 40 but as'soon as the core strikes against the head 43, it pulls the stem 40 'upwardly. The stem If? and its attached parts are relatively light as compared .to the core 39' and the kinetic energy of the core 39 tends to pull these parts upwardly dash pot'46 due to the fact that'the check valve 47 opens and allows air to enter the interior of the dash pot freely, As soon, however, as the core 39 drops upon the stem 40, due to the interruption of the current to the coil 38, and to the interruption of the magnetic force which had previously pulled the core 39 upwardly, the check valve'47 closes and the dash pot 46 prevents the rapid falling of the core 39 and the contacts The dash pot is. so set that it takes several seconds, possibly twenty seconds for the contacts 41 to re-e stablish the circuit.

Under normal conditions, the valve 49 is open, the coil48. being so constructed that the core 50 is held in its upper position on a very small current, that is, on a current which is much less than that taken by the dehydrator under normal operating conditions. Whenever this current is interrupted by opening of the contact 41, or by failure of voltage supply, the valve 49 closes and interrupts the flow of emulsion into the treater. By interrupting the circuit to the transformer 33 whenever short circuiting chains form, and by simultaneously shut ting off the flow of emulsion to the treater, I am able to break down the short circuiting chains and to. give the water an opportunity to settle. When a very wet oil is being supplied to the. treater, the con-..

contacts 41 will remain closed practically all of the time and the valve 49 will remain,

open practically all .the time.

During the operation of the treater,there is a continuous settling of water inside -the treater in the space inside the electrode 8 and in the space above the electrode 8. This water falls in the bottom of the treater and rises in the pipe29. The height of this pipe is made sulflicient to allow water to pass'therethrough, providing the treater is full. The point of junction between the pipes 29 and 31 is on the same level as the top of the treater. In practice the valve 28 may be regulated by hand or auteirfatically to withdraw this water at a constant rate so lon as emulsion is supplied to the treater. @enever the supply of emulsion ceases due either to the closing of the valve 39 or other causes, and the level of the oil in the treater tends to, fall below' the top Whenever the treater has gotten into normal operating shape, however, the

thereof, the flow of water is immediately shut off as there is not sufficient hydrostatic head to force it over the point of junction of the pipes 29 and 31.

I have found that by using an entirely closed tank,-l[ am able to prevent fires and explosions as the oil is not exposed to the air and the vapors produced from the oil are never mixed with oxygen inside the treater or in the neighborhood of electrical discharges. By using a stationary inner electrode and a rotating. outer electrode inside a stationary tank, I am able to greatly simplify the insulation problem, only one insulator being necessary to support the inner electrode 8 and by reason of this greatly simplified insulation problem, I am able to make a tight tank and to eliminate the fire hazard, while at the same time preserving the advantages to be gained from agitation. By providing means for automatically regulating the circuit externally and shutting oft the flow of oil whenever conditions in the trcater become unfavorable to dehydra tion, ll am able/to automatically regulate the operation of the treater so that short circuiting does not becomeserious. ll provide the reactance 53, however, in the circuit to the primary 34: for the purpose of controlling the maximum current which may occur during the momentary short circuiting period.

I claim as my invention:

1. In a dehydrator for petroleum emulsions, the combination of: a stationary tank; a stationary inner electrode in said tank, said inner electrode being insulated from said tank; an outer electrode, electrically connected to said tank and situated between said tank and said stationary inner electrode; means for rotating said outer electrode; and means for impressing an electromotive force between said inner electrode and said outer electrode.

2. In a dehydrator for petroleum emulsions, the combination of: a stationary tank; an inner electrode in said tank; an outer electrode in said tank; means for rotating one of said electrodes; and means for impressing an electromotive force between said electrodes.

3. In a dehydrator for petroleum emulsions, the combination of: an entirely enclosed stationary tank, an electrode in said tank; a shaft for rotating said electrode; a fluid tight joint about said shaft where it passes through the walls of said tank; structure forming a second electrode in [said tank; and means for impressing an electromotive force between said electrodes.

4. In a dehydrator for petroleum emulsions, the combination of: an entirely enclosed stationarytank; an electrode in said tank; a shaft for rotating said electrode;

a fluid tight joint about said shaft where it passes through the walls of said tank; structure forming a second electrode in said tank; means for insulating said second electrode from said tank; and means for impressing an electromotive force between said electrodes. r

5. lln a dehydrator the combination of: an entirely enclosed stationary tank; an

'electrode'in said tank; and means, for rotating said electrode.

In testimony whereof, l have hereunto set my hand at Los Angeles, California," this 1st day of September, 1920. (a

FORD W. HARRIS. 

